The field of tissue engineering combines bioengineering methods with the principles of life sciences to understand the structural and functional relationships in normal and pathological mammalian tissues. The goal of tissue engineering is the development and ultimate application of biological substitutes to restore, maintain, or improve tissue functions. Thus, through tissue engineering, it is possible to design and manufacture a bioengineered tissue in a laboratory. Bioengineered tissues can include cells that are usually associated with a native mammalian or human tissues and synthetic or exogenous matrix scaffolds. The new bioengineered tissue must be functional when grafted onto a host, and be permanently incorporated within the host's body or progressively bioremodeled by cells from the recipient host patient. Fabrication of a tissue equivalent without a support member or scaffold leads to scientific challenges in creating the new bioengineered tissue.